Robotically guided catheter

ABSTRACT

Apparatus is provided for use with a steerable catheter that includes a thumb control adapted to control a deflection of a distal tip of the catheter. The apparatus includes a robot, including an end-effector, adapted to be coupled to the thumb control, and a controller, adapted to drive the end-effector to deflect the distal tip by manipulating the thumb control.

FIELD OF THE INVENTION

The present invention relates generally to invasive medical instruments,and specifically to methods and apparatus for manipulating and steeringa catheter for diagnostic and therapeutic purposes.

BACKGROUND OF THE INVENTION

Mechanisms for moving, guiding and/or steering invasive medicalinstruments, such as catheters, in living tissue for therapeutic,diagnostic and surgical purposes are well known in the art. Technologieshave been developed that enable locating and tracking medical devicesinserted within the body, including determining the orientation of apoint on the device, such as the tip of a catheter. Locating a surgicalobject within living tissue can be accomplished in a variety of ways,including using various forms of electromagnetic or ultrasound energy.Numerous catheter steering and deflection mechanisms are known in theart.

U.S. Pat. No. 6,083,170 to Ben-Haim, which is assigned to the assigneeof the present application and is incorporated herein by reference,describes a flexible, elongate probe having a distal end for insertionthrough physiological tissue, typically through a lumen in the tissue.The probe includes a sensor, which generates signals indicative of acharacteristic of the tissue in a vicinity of the probe, and analignment mechanism, which deflects the distal end of the probe inresponse to the signals. The signals may be indicative of obstructionsor of the direction of a clear channel in the lumen.

U.S. Pat. No. 5,492,13.1 to Galel, which is incorporated herein byreference, describes a catheter guided by directional control inside abodily passage by a servo-type system which includes a sensor totransmit position, orientation or velocity information to amicroprocessor which is typically programmed with an error detectionalgorithm, and a motion control system. The motion control systemgenerates a signal representative of the change in position, orientationor velocity needed to guide the catheter along a prescribed course oftravel or in general to continuously adjust its position relative to atarget. This signal is transmitted to a directional steering system, aforward drive system, or both, to effect the change. The result isdescribed as a closed-loop servo system capable of automated,preprogrammed advancement and/or positioning of the distal catheter tipthrough branched and convoluted passages to a site where therapeuticaction is needed or from which diagnostic information is sought.

U.S. Pat. No. 5,779,623 to Bonnell, which is incorporated herein byreference, describes a remote-controlled device for selectivelypositioning a medical instrument within a predetermined region of space.The device includes a clamp having two pivotally mounted sectionsenabling the clamp to be placed in either an opened position or a closedposition. Each section has a drive wheel including an arc-shaped groovewhich accommodates the medical instrument when the clamp is placed inthe closed position. Each of the wheels has a coupling gear positionedand configured to pivot apart when the clamp is placed in the openposition with portions of teeth of the gears remaining engaged with eachother. One of the drive wheels is directly driven by a motor housed inone of the sections of the clamp.

U.S. Pat. No. 6,436,107 to Wang et al., which is incorporated herein byreference, describes a surgical system that includes aremotely-controlled surgical instrument coupled to a tool driver thatcan spin and actuate the instrument. The instrument includes an actuatorrod that is coupled to an end-effector and detachably connected to apush rod. The push rod can move relative to the handle to actuate theend-effector. The handle can be secured to the tool driver by insertingpins into corresponding slots that are located on both the instrumentand the tool driver.

U.S. Pat. No. 5,754,741 to Wang et al., which is incorporated herein byreference, describes a robotic system that moves a surgical instrumentin response to the actuation of a foot pedal that can be operated by thefoot of a surgeon. The robotic system has an end-effector that isadapted to hold a surgical instrument such as an endoscope. Theend-effector is coupled to a robotic arm assembly which can move theendoscope relative to the patient. The system includes a computer whichcontrols the movement of the robotic arm in response to input signalsreceived from the foot pedal.

U.S. Pat. Nos. 5,649,956 and 6,461,372 to Jensen et al., which areincorporated herein by reference, describe techniques for releasablyholding a surgical instrument, such as an endoscopic instrumentconfigured for delivery through a small percutaneous penetration in apatient. The instrument comprises an elongate shaft with a pair ofmounting pins laterally extending from the shaft between its proximaland distal ends. An instrument holder comprises a support having acentral bore and an axially extending slot for receiving the instrumentshaft and the mounting pins. A pair of locking slots are cut into thesupport transversely to and in communication with the axial slot so thatthe mounting pins can be rotated within the locking slots. Theinstrument support further includes a latch assembly for automaticallylocking the mounting pins within the locking slots to releasably couplethe instrument to the instrument holder. With this twist-lock motion,the surgeon is described as being able to rapidly engage and disengagevarious instruments from the holder during a surgical procedure, such asopen surgery, laparoscopy or thoracoscopy.

PCT Publication WO 99/45994 to Beyar, which is incorporated herein byreference, describes a remote control catheterization system including apropelling device, which controllably inserts a flexible, elongate probeinto the body of a patient. A control console, in communication with thepropelling device, includes user controls which are operated by a userof the system remote from the patient to control insertion of the probeinto the body by the propelling device.

U.S. patent application Publication 2002/0143326 to Foley et al., whichis incorporated herein by reference, describes techniques for assistinga surgeon in ablating conduction paths in tissue, such as heart tissue.A device can be configured to operate as a template that adheres to thetissue surface, and allows the surgeon to more easily sever theconduction path to form a lesion in a desired location. In particular,the template can be used to guide the surgeon's use of a surgicalinstrument along a desired ablation path. In some cases, the templatemay incorporate hardware that structurally supports the instrument fortravel along the ablation path.

U.S. Pat. No. RE 34,502 to Webster, Jr., which is incorporated herein byreference, describes a catheter comprising a symmetrical cylindricalcontrol handle, an elongate tubular catheter body, and a flexiblecatheter tip having a lumen offset from the axis of the catheter tip.The control handle comprises a housing having a piston chamber at itsdistal end. A piston is mounted in the piston chamber and is affordedlengthwise movement. The proximal end of the catheter body is fixedlyattached to the distal end of the piston. A puller wire is attached tothe housing and extends through the piston, through and coaxial with thecatheter body and into the offset lumen of the catheter tip where it isattached to the wall of the catheter tip. Lengthwise movement of thepiston relative to the housing results in deflection of the cathetertip.

U.S. Pat. No. 6,210,407 to Webster, Jr., which is incorporated herein byreference, describes a bi-directional catheter comprising an elongatedbody, a tip section and a control handle. The body has at least onelumen extending therethrough. The tip section is mounted at the distalend of the catheter body and has at least two diametrically-opposedoff-axis lumens, the first smaller than the second. The control handlecomprises at least two members longitudinally movable between first andsecond positions. The catheter further comprises first and second pullerwires. The proximal end of each puller wire is connected to anassociated movable member of the control handle. Each puller wireextends from the control handle through a lumen of the catheter body.The first puller wire extends into the first lumen in the tip section,and the second puller wire extends into the second lumen in the tipsection. The distal end of each puller wire is anchored to the tipsection. Proximal movement of a movable member relative to the catheterbody results in proximal movement of the puller wire associated withthat movable member relative to the catheter body, and thus deflectionof the tip section in the direction of the lumen in which that pullerwire extends.

U.S. Pat. Nos. 6,066,125 and 6,123,699 to Webster, Jr., which areincorporated herein by reference, describe omni-directional steerablecatheters, and U.S. Pat. Nos. 6,183,463 and 6,198,974 to Webster, Jr.,which are incorporated herein by reference, describe bi-directionalsteerable catheters.

U.S. Pat. No. 3,470,876 to Barchilon, which is incorporated herein byreference, describes a steerable catheter with a distal end that isguidable through 360 degrees by means of four guide lines extendingalong the length of the catheter and differentially operated in pairs.

U.S. Pat. No. 4,920,980 to Jackowski, which is incorporated herein byreference, describes a catheter having a wire member loosely positionedin a bore thereof. The wire member is secured to the catheter at aposition adjacent the distal end, such position being radially spacedfrom the axis of the catheter. The wire member extends through the boreand out of the proximal end of the catheter, so that the distal end ofthe catheter can be bent by pulling the wire member.

U.S. Pat. No. 5,489,270 to van Erp; U.S. Pat. Nos. 5,897,529, 5,938,603,5,964,757, 6,171,277 and 6,210,362 to Ponzi; U.S. Pat. No. 6,402,719 toPonzi et al.; and U.S. Pat. No. 6,165,139 to Damadian, all of which areincorporated herein by reference, describe steerable catheters.

U.S. Pat. No. 4,930,494 to Takehana et al., which is incorporated hereinby reference, describes an endoscope that is bent using a shape memoryalloy (SMA). The distal end of an insertion section of the endoscope isdivided into a plurality of segments, each of which includes a pair ofSMA coils which are arranged symmetrically with respect to an axis andmemorize a close-winding shape. As the SMA coils recovers theirmemorized shape, the distal end of the insertion section is bent. TheSMA coils are restored to the memorized shape when they are conductivelyheated by means of a current supply circuit. The current supply circuitcomprises an input unit for inputting a target value of the bend anglefor a leading segment, a sensor for detecting the distance of insertionof the insertion section, a detector circuit for detecting the bendangle of each segment, and means for controlling the amount of currentsupply so that the bend angle of the SMA coils agrees with a targetangle. The inputted angle is set as the target angle for the leadingsegment, and the detected bend angle of each segment is set as thetarget angle for each succeeding segment. The set value is renewed eachtime the insertion distance of the insertion section attains apredetermined distance.

Kühl C et al., in “Virtual endoscopy: from simulation to optimization ofan active endoscope,” ESAIM: Proceedings 12:84-93 (November 2002), whichis incorporated herein by reference, describe a polyarticulated deviceactuated with SMA springs for endoscopy.

Haga Y et al., in “Small diameter active catheter using shape memoryalloy coils,” Trans. IEE of Japan 120-E (No.11):509-514 (2000), which isincorporated herein by reference, describe an active catheter havingmany joints comprising SMA coil actuators.

Otsuka K et al., in “Science and technology of shape-memory alloys: newdevelopments,” MRS. Bulletin 27:91-100 (February 2002), which isincorporated herein by reference, present an overview of recent progressin the field of SMAs, including a discussion of fundamental SMAconcepts, and examples of applications.

Bar-Cohen Y, in “Transition of EAP material from novelty to practicalapplications—are we there yet?” Proceedings of EAPAD, Paper No. 4329-02(March 2001), which is incorporated herein by reference, presents areview of current efforts-and challenges in the-field of electroactivepolymers (EAPs), including the use of EAPs for catheter steeringelements.

Bar-Cohen Y et al., in “Electroactive polymers (EAP) characterizationmethods,” Proceedings of SPIE's 7th Annual International Symposium onSmart Structures and Materials, Paper No. 3987-04 (March 2000), which isincorporated herein by reference, describe a new testing procedure forbending EAPs, in order to quantify their electrical and mechanicalproperties.

Razavinejad A, in “Ionic polymer metal composites,” ELE 482 BME Seminar(March 2002), which is incorporated herein by reference, presents anoverview of ionic electroactive polymers (ionic EAPs, also known asionic polymer metal composites (IPMCs)), which bend in response to anelectrical activation as a result of the mobility of cations in thepolymer network.

PCT Publication WO 98/43530 to Zilberstein et al., which is assigned tothe assignee of the present invention and is incorporated herein byreference, describes an elongate probe having a longitudinal axis and adistal tip, and including at least one deflection mechanism, whichincludes an elastic flexible member, having distal and proximal ends andhaving a predetermined bending stiffness. The flexible member is fixedwithin the probe generally parallel to the longitudinal axis thereof.The probe further includes a pull wire having a distal end coupled tothe distal end of the flexible member, and a proximal end that istensioned longitudinally to deflect the probe.

U.S. Pat. No. 6,246,898 to Vesely et al., which is incorporated hereinby reference, describes a method for carrying out a medical procedureusing a 3-D tracking and imaging system. A surgical instrument, such asa catheter, probe, sensor, pacemaker lead, needle, or the like isinserted into a living being, and the position of the surgicalinstrument is tracked as it moves through a medium in a bodilystructure. The location of the surgical instrument relative to itsimmediate surroundings is displayed to improve a physician's ability toprecisely position the surgical instrument. The method is described asbeing able to be integrated with robotic surgery.

U.S. Pat. No. 6,470,205 to Bosselmann et al., which is incorporatedherein by reference, describes a medical instrument for insertion intoan examination subject, having an elongated instrument body formed by anumber of successively arranged rigid sections, with respective,successive sections being connected to one another via articulatedjoints which can be angled relative to one another. The instrument iseither fashioned in the nature of a robot arm, or as an instrument to bemanually guided.

PCT Publication WO 02/074178 to Brock et al., which is incorporatedherein by reference, describes a remotely controllable flexibleinstrument system for performing a medical procedure on a subject. Theinstrument system comprises: an instrument shaft having proximal anddistal ends, the shaft being insertable into a subject so as to disposethe distal end of the instrument shaft internally within a subject; ashaft mount coupled to the instrument shaft at the proximal end of theinstrument shaft; and a drive unit drivably coupled to the shaft mount.The instrument shaft comprises an elongated shaft that supports amedical procedure mechanism for performing the medical procedure at aninternal target site. The elongated shaft is constructed and arrangedsuch that some length of the shaft is inherently and sufficientlydeformable so as to readily flex and pass atraumatically through ananatomic passage of the subject. The instrument further includes aremote user interface having a user input device connected to anelectrical controller which receives commands from the user input deviceand transmits signals to the drive unit in accordance with manipulationsof the user input device by a user. The electrical controller includes acommand processing mechanism for controlling bending of one or moredeformable lengths of the elongated shaft and movement of the medicalprocedure mechanism in accordance with manipulations of the user inputdevice by the user.

U.S. Pat. No. 5,808,665 to Green, which is incorporated herein byreference, describes a teleoperator system with telepresence. The systemincludes right and left hand controllers for control of right and leftmanipulators through use of a servomechanism that includes a computer.The teleoperator system comprises an endoscopic surgical instrumentsuited for endoscopic surgery. The surgical instrument comprises acontrol servomechanism which operates an insertion section. Theinsertion section comprises a forearm, a wrist and an end-effector. Theend-effector is a modified surgical instrument such as retractors,electrosurgical cutters, electrosurgical coagulators, forceps, needleholders, scissors, blades and irrigators.

U.S. Pat. No. 5,339,799 to Kami et al., which is incorporated herein byreference, describes a medical system comprising a medical apparatusincluding an operation unit manipulated by a surgeon and a treatmentsection formed away from the operation unit for treating a subject, adetector or a pressure sensor for detecting a state of contact betweenthe subject and the treatment section, and a reproduction mechanism foramplifying a small contact pressure according to the output of thedetector and thus reproducing the state of contact so that the surgeoncan perceive the state of contact.

U.S. patent application Publication 2002/0128636 to Chin et al., whichis incorporated herein by reference, describes techniques forpositioning a medical instrument at a desired biological target tissuesite. The system includes an elongated sheath having a deflectabledistal end configured to deflect or otherwise position at least aportion of a medical instrument during a surgical procedure, allowingfor the placement of the deflected portion adjacent or proximate to apredetermined target tissue surface. The positioning system may beincorporated into the medical instrument. The medical instrument may bean ablation system. The medical instrument may be controlled by a robotduring a robotic minimally invasive surgical procedure. The robot cantelescopically translate or rotate the medical instrument in order toposition the ablation sheath and the ablation element correctly toproduce the ablation of tissue.

U.S. Pat. No. 5,078,140 to Kwoh, which is incorporated herein byreference, describes a method for computer-controlled stereotacticsurgery. The method utilizes an imaging device, a robotic arm, and ameans for controlling the robotic arm. The imaging device providesinformation regarding the structure of the bodily location to beoperated on. The robotic arm is utilized to precisely orient thesurgical tools or other implements used in conducting the surgery orrelated procedure. The control means, such as a computer, utilizesinformation received from the imaging device, alone or together withother information, to control the robotic arm.

U.S. Pat. No. 6,490,467 to Bucholz et al., which is incorporated hereinby reference, describes a system for use during a medical or surgicalprocedure on a body. The system generates an image representing theposition of one or more body elements during the procedure using scansgenerated by a scanner prior to or during the procedure. The image dataset has reference points for each of the body elements, the referencepoints of a particular body element having a fixed spatial relation tothe particular body element. The system includes an apparatus foridentifying, during the procedure, the relative position of each of thereference points of each of the body elements to be displayed.

U.S. patent application Publication 2002/0087151 to Mody et al., whichis incorporated herein by reference, describes techniques for ablating aselected portion of a contact surface of biological tissue. The systemincludes an elongated ablation sheath having a preformed shape adaptedto substantially conform a predetermined surface thereof with thecontact surface of the tissue. The ablation sheath defines an ablationlumen sized to slidably receive an elongated ablative devicelongitudinally therethrough. The ablative device includes a flexibleablation element selectively generating an ablative field sufficientlystrong to cause tissue ablation. Advancement of the ablation elementslidably through the ablation lumen of the ablation sheath selectivelyplaces the ablation element along the ablation path for guided ablationon the contact surface when the predetermined surface is in suitablecontact therewith. The ablation sheath or ablation element can becontrolled by a robot during a robotic minimally-invasive surgicalprocedure. The robot can telescopically translate or rotate the ablationsheath or ablation element in order to position the ablation sheath andthe ablation element correctly to produce the ablation of tissue.

U.S. Pat. No. 6,400,980 to Lemelson, which is incorporated herein byreference, describes a computerized imaging system that is employed tosense the position of an endoscopic treatment system within the body ofa patient. In a preferred embodiment, the system provides real-timecomputer control to maintain and adjust the position of the treatmentsystem and/or the position of the patient relative to the treatmentsystem; and also optionally provides real-time computer control of theoperation of the treatment system itself. Other embodiments include asteerable catheter system having a rotatable abrasive member actuated byan external magnetic field.

U.S. Pat. No. 5,681,260 to Ueda et al., which is incorporated herein byreference, describes guiding apparatus for guiding an insertable bodywithin an inspected object. The guiding apparatus comprises a guidedpart and a guiding device provided outside the inspected object, adaptedto magnetically guide the guided part. The guiding device includes adriving device for moving the guiding part at least two-dimensionally.

U.S. Pat. Nos. 6,507,751, 6,014,580, 6,212,419, and 6,157,853 to Blumeet al., which are incorporated herein by reference, describe methods,including interactive displays, of modifying magnetic fields to move orguide surgically implanted objects which comprise magnetic material.

U.S. Pat. No. 6,475,223 to Werp et al., which is incorporated herein byreference, describes a method for moving an implant in the body byapplying mechanical pushing forces and magnetically steering the implanton a predetermined path by means of making changes in an externallyapplied magnetic system.

U.S. Pat. No. 5,125,888 to Howard et al., which is incorporated hereinby reference, describes a method of observing the location and movementof a magnetic object within the body, employing magnetic systems.

U.S. Pat. No. 4,173,228 to Van Steenwyk et al.; U.S. Pat. Nos.5,558,091, 5,729,129, and 5,752,513 to Acker et al.; and U.S. Pat. No.5,833,608 to Acker, all of which are incorporated herein by reference,describe methods and apparatus for magnetic determination of positionand orientation.

U.S. Pat. Nos. 5,546,951 and 6,066,094 to Ben-Haim, and European Patent0 776 176 to Ben-Haim et al., which are assigned to the assignee of thepresent patent application and are incorporated herein by reference,describe methods for sensing an electrical property of heart tissue, forexample, local activation time, as a function of the precise locationwithin the heart. The data are acquired with a catheter that haselectrical and location sensors in its distal tip, and which is advancedinto the heart. Techniques for sensing cardiac electrical activity arealso described in U.S. Pat. No. 5,471,982 to Edwards et al.,commonly-assigned U.S. Pat. Nos. 5,391,199 and 6,066,094 to Ben-Haim,U.S. Pat. No. 6,052,618 to Dahlke et al., and in PCT Patent PublicationsWO 94/06349 and WO 97/24981, which are incorporated herein by reference.

Methods of creating a map of the electrical activity of the heart basedon these data are disclosed in U.S. Pat. Nos. 6,226,542 and 6,301,496 toReisfeld, which are assigned to the assignee of the present patentapplication and are incorporated herein by reference. As indicated inthese patents, location and electrical activity is typically initiallymeasured on about 10 to about 20 points on the interior surface of theheart. These data points are then generally sufficient to generate apreliminary reconstruction or map of the cardiac surface to asatisfactory quality. The preliminary map is often combined with datataken at additional points in order to generate a more comprehensive mapof the heart's electrical activity. In clinical settings, it is notuncommon to accumulate data at 100 or more sites to generate a detailed,comprehensive map of heart chamber electrical activity. The generateddetailed map may then serve as the basis for deciding on a therapeuticcourse of action, for example, tissue ablation, which alters thepropagation of the heart's electrical activity and restores normal heartrhythm. Methods for constructing a cardiac map of the heart are alsodisclosed in U.S. Pat. Nos. 5,391,199 and 6,285,898 to Ben-Haim, and inU.S. Pat. Nos. 6,368,285 and 6,385,476 to Osadchy et al., which areassigned to the assignee of the present patent application and areincorporated herein by reference.

European Patent Application EP 1 125 549 and corresponding U.S. patentapplication Ser. No. 09/506,766 to Ben-Haim et al., which are assignedto the assignee of the present patent application and are incorporatedherein by reference, describe techniques for rapidly generating anelectrical map of a chamber of the heart. The catheter used for thesetechniques comprises a contact electrode at the distal tip of thecatheter and an array of non-contact electrodes on the shaft of thecatheter near the distal end. The catheter also comprises at least oneposition sensor. Information from the non-contact electrodes and contactelectrode is used for generating a geometric and electrical map of thecardiac chamber.

SUMMARY OF THE INVENTION

In embodiments of the present invention, a robotic guided cathetersystem comprises a catheter, a control mechanism, and a console. Thecatheter typically comprises at least one position sensor located in avicinity of a distal tip of the catheter. During a medical procedure,the catheter is inserted into an area of interest of a subject, such asa body cavity (e.g., a heart) or a physiological lumen (e.g., a bloodvessel or a digestive tract), and the console generates a map of thearea of interest. A user of the system indicates a position at which thedistal tip is to be positioned, and the console drives the controlmechanism to position the distal tip at the desired position.

In some embodiments of the present invention, the catheter comprises ahuman-controllable steerable catheter capable of being manuallymanipulated by a user, such as catheters that are widely commerciallyavailable and used today. The control mechanism comprisesmanually-controllable means for deflecting the distal tip of thecatheter, such as a control handle and/or a thumb control. The controlmechanism further comprises a robotic control mechanism, which isadapted to hold and manipulate the catheter by generally mimicking themotions of a hand of a surgeon.

In some embodiments of the present invention, the catheter comprises anautomated catheter, adapted to be primarily robotically controlled. Thecontrol mechanism comprises an integrated robotic control mechanism,which comprises a plurality of puller wires, e.g., four. The pullerwires are disposed about the circumference of the catheter and extendalong its length, typically passing through respective lumens. Thedistal ends of the puller wires are attached at respective points in avicinity of the distal end of the catheter, and the proximal ends of thewires are coupled to respective motors. The motors are able to tense andrelax the respective puller wires. Typically, by selective activation ofrespective motors, the control mechanism is able to manipulate thedistal end of the catheter through 360 degrees of deflection.Alternatively, the integrated robotic control mechanism comprises asteering mechanism that utilizes shape memory alloys (SMAs),electroactive polymers (EAPs), and/or ionic polymer metal composites(IPMCs).

In some embodiments of the present invention, the position sensor isadapted to generate six dimensions of location and orientationinformation, typically continuously. The console is adapted to determinethe roll of the catheter in a vicinity of the distal tip thereof, byusing the six dimensions of information. The control mechanism and thecatheter typically comprise robotic means for deflecting the distal tipin either (a) a single direction, for any given roll of the distal tip,or (b) in two opposing directions, for any given roll of the distal tip.In order to position the distal tip at a desired target, the console isadapted to: drive the control mechanism to robotically move the distaltip into a vicinity of the target; roll the catheter so that the targetintersects a curve defined by the points to which the distal tip is ableto deflect, given the roll of the distal tip; and deflect the distal tipto the target.

In some embodiments of the present invention, when the control mechanismattempts to roll the distal tip of the catheter, rotation of a proximalend of the catheter in a vicinity of the control mechanism sometimesdoes not translate into equivalent roll of the distal tip. For example,the distal tip may sometimes become slightly caught on tissue of thearea of interest. As the control mechanism rotates the proximal end,torque builds up in the catheter, until the torque is sufficient tocause the distal tip to come free from the tissue and rotate suddenly.In some embodiments of the present invention, the position sensor isadapted to generate six dimensions of location and orientationinformation, typically continuously. The console is adapted to determinethe roll of the catheter in a vicinity of the distal tip, by using thesix dimensions of information. When the console drives the controlmechanism to rotate the catheter, the console substantiallysimultaneously determines the roll of the distal tip, and compares thisroll with the expected roll based on the known rotation of the proximalend of the catheter. If the console detects a lag of the roll of thedistal tip with respect to the rotation of the proximal end of thecatheter, the console drives the control mechanism to attempt to movethe distal tip in order to free the distal tip from tissue on which thetip is presumably caught. For example, the console may drive the controlmechanism to:

-   -   (a) straighten and/or deflect the distal tip,    -   (b) jiggle the distal tip until it comes free from the tissue,        such as by quickly, repeatedly, rhythmically or irregularly        rotating the proximal end back and forth by a few degrees,    -   (c) translationally move the distal tip back and forth (e.g.,        left/right, up/down), and/or    -   (d) advance and/or withdraw the distal tip.

There is therefore provided, in accordance with an embodiment of thepresent invention, apparatus for use with a steerable catheter thatincludes a thumb control adapted to control a deflection of a distal tipof the catheter, the apparatus including a robot, including:

-   -   an end-effector, adapted to be coupled to the thumb control; and    -   a controller, adapted to drive the end-effector to deflect the        distal tip by manipulating the thumb control.

For some applications, the controller is adapted to drive theend-effector to deflect the distal tip by moving the thumb controllongitudinally with respect to a longitudinal axis of the catheter.

For some applications, the catheter includes a handle, adapted tocontrol a roll of the distal tip; the robot includes a handleend-effector, adapted to be coupled to the handle; and the controller isadapted to drive the handle end-effector to roll the distal tip bymanipulating the handle. Alternatively or additionally, the catheterincludes a handle, adapted to advance and withdraw the catheter; therobot includes a handle end-effector, adapted to be coupled to thehandle; and the controller is adapted to drive the handle end-effectorto perform, by manipulating the handle, at least one action selectedfrom the list consisting of: advancing the catheter and withdrawing thecatheter.

In an embodiment of the present invention, the apparatus includes acomputer pointing device, adapted to receive an indication of a desiredposition of the distal tip; the catheter includes a position sensor,fixed in a vicinity of the distal tip, and adapted to generate aposition signal; and the controller is adapted to receive the positionsignal, and, responsive thereto, to drive the end-effector to positionthe distal tip at the desired position.

There is further provided, in accordance with an embodiment of thepresent invention, apparatus including:

-   -   a steerable catheter, including a thumb control, which is        adapted to control a deflection of a distal tip of the catheter;        and    -   a robot, including:        -   an end-effector, adapted to be coupled to the thumb control;            and        -   a controller, adapted to drive the end-effector to deflect            the distal tip by manipulating the thumb control.

There is also provided, in accordance with an embodiment of the presentinvention, apparatus for use with a steerable catheter that includescontrols adapted to control a deflection of a distal tip of thecatheter, which controls are generally optimized for manipulation by ahuman hand, the apparatus including a robot, including:

-   -   at least one end-effector, adapted to be coupled to at least a        portion of the controls; and    -   a controller, adapted to drive the at least one end-effector to        deflect the distal tip by inducing motion of the portion of the        controls that generally mimics motion of the portion of the        controls induced when a human hand manipulates the controls.

For some applications, the controller is adapted to drive theend-effector to deflect the distal tip by moving the portion of thecontrols longitudinally with respect to a longitudinal axis of thecatheter.

For some applications, the controls are adapted to control a roll of thedistal tip; the robot includes a roll end-effector, adapted to becoupled to the controls; and the controller is adapted to drive the rollend-effector to roll the distal tip by inducing motion of the controlsthat generally mimics motion of the controls induced when a human handmanipulates the controls. Alternatively or additionally, the controlsare adapted to advance and withdraw the catheter; the robot includes alongitudinal motion end-effector, adapted to be coupled to the controls;and the controller is adapted to drive the longitudinal motionend-effector to perform, by inducing motion of the controls thatgenerally mimics motion of the controls induced when a human handmanipulates the controls, at least one action selected from the listconsisting of: advancing the catheter and withdrawing the catheter.

In an embodiment of the present invention, the apparatus includes acomputer pointing device, adapted to receive an indication of a desiredposition of the distal tip; the catheter includes a position sensor,fixed in a, vicinity of the distal tip, and adapted to generate aposition signal; and the controller is adapted to receive the positionsignal, and, responsive thereto, to drive the end-effector to positionthe distal tip at the desired position.

There is additionally provided, in accordance with an embodiment of thepresent invention, apparatus including:

-   -   a steerable catheter, including controls adapted to control a        deflection of a distal tip of the catheter, which controls are        generally optimized for manipulation by a human hand; and    -   a robot, including:        -   at least one end-effector, adapted to be coupled to at least            a portion of the controls; and        -   a controller, adapted to drive the at least one end-effector            to deflect the distal tip by inducing motion of the portion            of the controls that generally mimics motion of the portion            of the controls induced when a human hand manipulates the            controls.

There is yet additionally provided, in accordance with an embodiment ofthe present invention, apparatus including:

-   -   a steerable catheter, including:        -   a distal tip adapted to be controllably deflectable in no            more than two directions for any given rotation of the            distal tip, such that a set of all points to which the tip            can be deflected at the given rotation forms a deflection            curve for the given rotation; and        -   a position sensor, fixed in a vicinity of the distal tip,            and adapted to generate a position signal;    -   a robot, adapted to manipulate a proximal end of the catheter;        and    -   a control unit, adapted to:    -   receive the position signal, and    -   position the distal tip at a target by driving the robot to:        -   position the distal tip in a vicinity of the target,            responsive to the position signal,        -   rotate the proximal end in order to cause the distal tip to            roll to a rotation the deflection curve of which includes            the target, the rotation determined responsive to the            position signal, and        -   deflect the distal tip along the deflection curve to the            target.

For some applications, the distal tip is adapted to be controllablydeflected in no more than one direction for the given rotation of thedistal tip. For some applications, the control unit is adapted toposition the distal tip in the vicinity of the target by positioning thedistal tip so that the deflection curve of at least one rotation of thedistal tip includes the target.

In an embodiment of the present invention, the apparatus includes acomputer pointing device, adapted to receive an indication of a positionof the target, and the control unit is adapted to drive the robot toposition the distal tip at the position of the target, responsive to theposition signal.

For some applications, the position sensor is adapted to generate theposition signal having six dimensions of position and orientationinformation.

There is still additionally provided, in accordance with an embodimentof the present invention, apparatus including:

-   -   a steerable catheter having a distal tip, the catheter including        a position sensor, fixed in a vicinity of the distal tip, and        adapted to generate a position signal;    -   a robot, adapted to be coupled to a proximal end of the        catheter; and    -   a control unit, adapted to:        -   drive the robot to apply rotation to the proximal end of the            catheter,        -   receive the position signal,        -   responsive to the position signal, determine a roll of the            distal tip, and        -   responsive to a determination that the roll lags the            rotation, drive the robot to move a portion of the proximal            end of the catheter.

For some applications, the control unit is adapted to drive the robot tomove the portion of the proximal end of the catheter to perform at leastone action selected from the list consisting of: straightening thedistal tip and deflecting the distal tip. Alternatively or additionally,the control unit is adapted to drive the robot to move the portion ofthe proximal end of the catheter to effect translational back and forthmotion of the distal tip. Further alternatively or additionally, thecontrol unit is adapted to drive the robot to move the portion of theproximal end of the catheter to perform at least one action selectedfrom the list consisting of: advancing the distal tip and withdrawingthe distal tip.

For some applications, the position sensor is adapted to generate theposition signal having six dimensions of position and orientationinformation.

For some applications, the control unit is adapted to move the portionof the proximal end of the catheter to jiggle the distal tip. Forexample, the control unit may jiggle the distal tip by rotating theproximal end of the catheter.

There is still further provided, in accordance with an embodiment of thepresent invention, a method for use with a steerable catheter thatincludes a thumb control adapted to control a deflection of a distal tipof the catheter, the method including:

-   -   coupling a robotic end-effector to the thumb control; and    -   driving the end-effector to deflect the distal tip by        manipulating the thumb control.

There is also provided, in accordance with an embodiment of the presentinvention, a method for use with a steerable catheter that includescontrols adapted to control a deflection of a distal tip of thecatheter, which controls are generally optimized for manipulation by ahuman hand, the method including:

-   -   coupling at least one robotic end-effector to at least a portion        of the controls; and    -   driving the at least one end-effector to deflect the distal tip        by inducing motion of the portion of the controls that generally        mimics motion of the portion of the controls induced when a        human hand manipulates the controls.

There is further provided, in accordance with an embodiment of thepresent invention, a method for use with a steerable catheter having adistal tip adapted to be controllably deflectable in no more than twodirections for any given rotation of the distal tip, such that a set ofall points to which the tip can be deflected at the given rotation formsa deflection curve for the given rotation, the method including:

-   -   receiving a position signal from a vicinity of the distal tip;        and    -   robotically positioning the distal tip at a target by:        -   robotically positioning the distal tip in a vicinity of the            target, responsive to the position signal,        -   robotically rotating the proximal end in order to cause the            distal tip to roll to a rotation the deflection curve of            which includes the target, the rotation determined            responsive to the position signal, and        -   robotically deflecting the distal tip along the deflection            curve to the target.

There is still further provided, in accordance with an embodiment of thepresent invention, a method for use with a steerable catheter having adistal tip and a proximal end, the method including:

-   -   robotically rotating the proximal end of the catheter;    -   receiving a position signal from a vicinity of the distal tip of        the catheter;    -   responsive to the position signal, determining a roll of the        distal tip; and    -   responsive to a determination that the roll lags the rotation,        robotically moving a portion of the proximal end of the        catheter.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a robotic guided catheter system,in accordance with an embodiment of the present invention;

FIG. 2 is a schematic illustration of a robotic control mechanism, inaccordance with an embodiment of the present invention;

FIG. 3 is a schematic illustration of another robotic control mechanism,in accordance with an embodiment of the present invention; and

FIG. 4 is a schematic illustration of deflection of a distal tip of acatheter, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic illustration of a robotic guided catheter system10, in accordance with an embodiment of the present invention. Cathetersystem 10 comprises a catheter 20, a control mechanism 22, and a console24. Catheter 20 is adapted to be inserted into an area of interest 25 ofa subject, such as a body cavity (e.g., a heart) or a physiologicallumen (e.g., a blood vessel or a digestive tract). Console 24 typicallycomprises a display monitor 26 and a computer 28. Computer 28 isprogrammed in software and/or hardware to carry out the functionsdescribed herein. This software may be downloaded to the computer inelectronic form, over a network, for example, or it may alternatively beprovided on tangible media, such as magnetic or optical media or othernon-volatile memory. For some applications, computer 28 comprises ageneral-purpose computer.

Catheter 20 typically comprises at least one position sensor 30 and atleast one tool 32, both located in a vicinity of a distal tip 34 of thecatheter. For example, tool 32 may comprise a sensing electrode, anablating element, a temperature sensor, or an ultrasound transducer.

Position sensor 30 generates or receives signals used to determine theposition and orientation of catheter 20. Suitable position sensors aredescribed, for example, in the above-referenced U.S. Pat. No. 5,391,199to Ben-Haim, the above-referenced European Patent 0 776 176 to Ben-Haimet al., co-pending U.S. patent application Ser. No. 10/029,473, filedDec. 21, 2001, entitled, “Wireless position sensor,” and/or inco-pending U.S. patent application Ser. No. 10/029,595, also filed Dec.21, 2001, entitled, “Implantable and insertable tags,” all of which areassigned to the assignee of the present patent application and areincorporated herein by reference. Alternatively or additionally,substantially any other suitable type of position/coordinate sensingdevice known in the art is used for position sensing. Still furtheralternatively or additionally, catheter 20 is marked with one or moremarkers whose positions can be determined from outside of the body.Suitable markers include radio-opaque markers to facilitate fluoroscopicmeasurements. Preferably, position-sensing techniques are used thatachieve continuous generation of up to six dimensions of location andorientation information with respect to position sensor 30.

Typically, catheter system 10 further comprises a set of externalradiators 36, which are adapted to be located at respective positionsexternal to the subject in a vicinity of area of interest 25. For someapplications, radiators 36 are adapted to generate fields, such aselectromagnetic fields, towards position sensor 30, which is adapted todetect the fields. Alternatively, position sensor 30 generates fields,which are detected by radiators 36. For some applications, a referenceposition sensor, typically either on an externally-applied referencepatch attached to the exterior of the body of the subject, or on aninternally-placed catheter, is maintained in a generally fixed positionrelative to area of interest 25. By comparing the position of catheter20 to that of the reference catheter, the coordinates of catheter 20 areaccurately determined relative to the area of interest, irrespective ofmotion of the subject. Alternatively, any other suitable method may beused to compensate for such motion.

During a medical procedure, catheter 20 is inserted into area ofinterest 25. Console 34 typically generates a map 37 of the area ofinterest. For example, techniques may be used that are described in theabove-cited U.S. Pat. Nos. 6,226,542 and 6,301,496 to Reisfeld, Europeanpatent application EP 1 125 549 and corresponding U.S. patentapplication Ser. No. 09/506,766 to Ben-Haim et al., and/or co-pendingU.S. patent application Ser. No. 09/598,862 to Govari, all of which areincorporated herein by reference, adapted for use with the techniquesdescribed herein. Alternatively, techniques known in the art, e.g.,imaging modalities, are used for generating map 37. Map 37 is displayedon monitor 26 with an indication of the location of distal tip 34 ofcatheter 20 superimposed upon it, typically using position informationgenerated from position sensor 30.

In an embodiment of the present invention, computer 28 calculatespotential positions in a vicinity of the current position of distal tip34, to which the distal tip can be repositioned. These potentialpositions are designated on map 37. A user of the system points a cursorat or in a vicinity of one of these potential positions, using acomputer pointing device such as a mouse, keyboard, joystick or touchsensitive screen. Computer 28 drives control mechanism 22 to positiondistal tip 34 at the desired position.

For some applications, in order to drive control mechanism 22, computer28 implements an algorithm that uses an iterative process to directdistal tip 26 to the desired position, responsive to positioninformation generated by position sensor 30 at each iteration. Bycontinuously checking the location of distal tip 34 and appropriatelydriving the control mechanism, the computer precisely controls thelocation of distal tip 34, regardless of the particular structure ofcatheter 20 or characteristics of the tissue surrounding catheter 20 atany given time. Additionally, for some applications, computer 28 usesinformation generated during the iterative process concerning locationand motion of distal tip 34, to perform continuous real-time calibrationof the system, thus ensuring reliability and accuracy of the systemregardless of the character of the tissue through which the catheter isbeing guided.

Reference is now made to FIG. 2, which is a schematic illustration of arobotic control mechanism 38 attached to catheter 20, in accordance withan embodiment of the present invention. In this embodiment, catheter 20comprises a human-controllable steerable catheter 40 capable of beingmanually manipulated by a surgeon, such as catheters that are widelycommercially available and used today. Catheter 40 comprisesmanually-controllable means for deflecting a distal tip 42 of thecatheter, such as a control handle 44 and/or a thumb control 46. Forexample, the catheter may utilize techniques described in one or more ofthe above-referenced U.S. Pat. Nos. RE 34,502, 3,470,876, 4,920,980,5,489,270, 5,897,529, 5,938,603, 5,964,757, 6,066,125, 6,123,699,6,165,139, 6,171,277, 6,183,463, 6,198,974, 6,210,362, 6,210,407, and6,402,719, and/or in the above-referenced PCT Publication WO 98/43530.

Control mechanism 22 comprises robotic control mechanism 38, which isadapted to hold and manipulate human-controllable catheter 40 so as toinduce motions of the manually-controllable means that mimic thosecaused when the manually-controllable means are adjusted by a hand of asurgeon. Robotic control mechanism 38 comprises a controller 48 and oneor more end-effectors, such as a proximal gripper 50 and a distalgripper 52. In the exemplary configuration shown in FIG. 2, proximalgripper 50 is adapted to grip handle 44, to move the handle in distaland proximal directions, and to rotate the handle. Robotic controlmechanism 38 comprises a motor 58 or other actuator to induce therotation of proximal gripper 50 and consequently of catheter 40. (Forclarity, some supporting structure is not shown in the figure.) Movingthe handle and thumb control 46 in concert in distal and proximaldirections causes distal tip 42 of the catheter to advance and withdraw,respectively, while rotating handle 44 generally rotates the distal tip.Distal gripper 52 is adapted to grip thumb control 46, and to move thethumb control in distal and proximal directions, typically whileproximal gripper 50 remains stationary, so as to manipulate one or morepuller wires that pass through one or more lumens (not shown) ofcatheter 40. Alternatively, proximal gripper 50 moves while thumbcontrol 46 remains stationary, in order to manipulate the one or morepuller wires. Manipulation of the puller wires typically deflects distaltip 42 in an arc. Alternatively, handle 44 and/or thumb control 46 useother techniques known in the art for manipulating catheter 40 and/ordeflecting distal tip 42. Adaptations of control mechanism 22 tomanipulate and control catheters other than that of the exemplaryembodiment shown in FIG. 2 will be apparent to those skilled in the art,having read the present patent application. For example, the controlmechanism may be adapted to deflect distal tip 42 independently in x-and y-axes. Typically, but not necessarily, the initial insertion ofcatheter 40 into area of interest 25 is performed manually by thesurgeon, who then attaches the end-effectors of robotic controlmechanism 38 to catheter 40.

Reference is now made to FIG. 3, which is a schematic illustration of anintegrated robotic control mechanism 82, in accordance with anembodiment of the present invention. In this embodiment, catheter 20comprises an automated catheter 80, adapted to be primarily roboticallycontrolled. Control mechanism 22 comprises integrated robotic controlmechanism 82, which comprises a plurality of puller wires 83, e.g.,four. Puller wires 83 are disposed about the circumference of thecatheter and extend along its length, passing through respective lumens84. Typically, the catheter also comprises a spine 86. (Only three ofthe plurality of puller wires, and two of lumens 84, are shown in FIG. 3for clarity of illustration.) The distal ends of puller wires 83 areattached at respective points 88 in a vicinity of a distal end 90 ofcatheter 80, and the proximal ends of the wires are coupled torespective motors 92. Motors 92 are able to tense and relax (or push andpull, depending upon the characteristics of the wire material) therespective puller wires. In this manner, by selective activation ofrespective motors 92, control mechanism 82 is able to manipulate distalend 90 through 360 degrees of deflection. By applying tension to some orall puller wires 83 simultaneously, control mechanism 82 withdrawscatheter 80 in a proximal direction. By extending some or all of thewires and/or by extending spine 86, the control mechanism advances thecatheter in a distal direction.

Alternatively or additionally, automated catheter 80 and/or integratedrobotic control mechanism 82 utilize robotic control techniques known inthe art, for example those described in the above-referenced U.S. Pat.No. 5,078,140, U.S. Pat. No. 5,492,131, U.S. patent applicationPublication 2002/0087151, U.S. patent application Publication2002/0128636, PCT Publication WO 99/45994, and/or PCT Publication WO02/074178.

In an embodiment of the present invention, integrated robotic controlmechanism 82, rather than comprising puller wires 83, comprises asteering mechanism that utilizes shape memory alloys (SMAs),electroactive polymers (EAPs), and/or ionic polymer metal composites(IPMCs). For example, techniques and/or materials may be used that aredescribed in one or more of the above-mentioned U.S. Pat. No. 4,930,494to Takehana et al., and articles by Kühl C et al., Haga Y et al., OtsukaK et al., Bar-Cohen Y, Bar-Cohen Y et al., and Razavinejad A.

Reference is now made to FIG. 4, which is a schematic illustration ofdeflection of distal tip 34 of catheter 20, in accordance with anembodiment of the present invention. In this embodiment, position sensor30 is adapted to generate six dimensions of location and orientationinformation, typically continuously. Computer 28 (FIG. 1) is adapted todetermine the roll of catheter 20 in a vicinity of distal tip 34, byusing the six dimensions of information. In this embodiment, controlmechanism 22 (FIG. 1) and catheter 20 typically comprise robotic meansfor deflecting distal tip 34 in either (a) a single direction, asindicated by an arrow 100, for any given roll of the distal tip, or (b)in two opposing directions, as indicated by arrow 100 and an arrow 102,for any given roll of the distal tip. Control mechanism 22 comprises (a)robotic control mechanism 38, described hereinabove with reference toFIG. 2, (b) integrated robotic control mechanism 82, describedhereinabove with reference to FIG. 3, or (c) another robotic controlmechanism known in the art, including those described in the referencescited in the Background of the Invention.

In order to position distal tip 34 at a desired target 104, computer 28is adapted to drive control mechanism 22 to robotically:

-   -   move distal tip 34 into a vicinity of target 104;    -   roll catheter 20 so that the target intersects a curve 106        defined by the points to which distal tip 34 is able to deflect,        given the roll of the distal tip. Computer 28 determines the        roll using the six degrees of position information generated by        position sensor 30. If necessary, computer 28 additionally        drives control mechanism 22 to advance or withdraw distal tip 34        in order to position distal tip 34 so that curve 106 intercepts        target 104; and    -   deflect distal tip 34 to target 104.

Reference is again made to FIG. 1. When control mechanism 22 attempts toroll distal tip 34 of catheter 20, rotation of a proximal end 120 ofcatheter 20 in a vicinity of control mechanism 22 sometimes does nottranslate into equivalent roll of distal tip 34. For example, distal tip34 may sometimes become slightly caught on tissue of area of interest25. As control mechanism 22 rotates proximal end 120, torque builds upin the catheter, until the torque is sufficient to cause distal tip 34to come free from the tissue and rotate suddenly.

In an embodiment of the present invention, position sensor 30 is adaptedto generate six dimensions of location and orientation information,typically continuously. Computer 28 is adapted to determine the roll ofcatheter 20 in a vicinity of distal tip 34, by using the six dimensionsof information. When computer 28 drives control mechanism 22 to rotatecatheter 20, the computer substantially simultaneously determines theroll of distal tip 34, and compares this roll with the expected rollbased on the known rotation of proximal end 120 of catheter 20. If thecomputer detects a lag of the roll of distal tip 34 with respect to therotation of proximal end 120, the computer drives control mechanism 22to attempt to move the catheter in order to free distal tip 34 fromtissue on which the tip is presumably caught. For example, the computermay drive the control mechanism to:

-   -   (a) straighten and/or deflect distal tip 34,    -   (b) jiggle distal tip 34 until it comes free from the tissue,        such as by quickly, repeatedly, rhythmically or irregularly        rotating proximal end 120 back and forth by a few degrees,    -   (c) translationally move the distal tip back and forth, and/or    -   (d) advance and/or withdraw distal tip 34.

For some applications, computer 28 implements an expert system thatevaluates the lag of the roll of distal tip 34 with respect to therotation of proximal end 120. Responsive to measured or calculatedvariables, such as the magnitude of the lag and/or the timing of thelag, computer 28 determines which mechanical stimulation to apply to thecatheter, the magnitude of such stimulation, and/or the timing of suchstimulation. For some applications, the expert system may utilize alookup table.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1. Apparatus for use with a steerable catheter that includes a thumbcontrol adapted to control a deflection of a distal tip of the catheter,the apparatus comprising a robot, comprising: an end-effector, adaptedto be coupled to the thumb control; and a controller, adapted to drivethe end-effector to deflect the distal tip by manipulating the thumbcontrol.
 2. The apparatus according to claim 1, wherein the controlleris adapted to drive the end-effector to deflect the distal tip by movingthe thumb control longitudinally with respect to a longitudinal axis ofthe catheter.
 3. The apparatus according to claim 1, wherein thecatheter includes a handle, adapted to control a roll of the distal tip,wherein the robot comprises a handle end-effector, adapted to be coupledto the handle, and wherein the controller is adapted to drive the handleend-effector to roll the distal tip by manipulating the handle.
 4. Theapparatus according to claim 1, wherein the catheter includes a handle,adapted to advance and withdraw the catheter, wherein the robotcomprises a handle end-effector, adapted to be coupled to the handle,and wherein the controller is adapted to drive the handle end-effectorto perform, by manipulating the handle, at least one action selectedfrom the list consisting of: advancing the catheter and withdrawing thecatheter.
 5. The apparatus according to claim 1, comprising a computerpointing device, adapted to receive an indication of a desired positionof the distal tip, wherein the catheter includes a position sensor,fixed in a vicinity of the distal tip, and adapted to generate aposition signal, and wherein the controller is adapted to receive theposition signal, and, responsive thereto, to drive the end-effector toposition the distal tip at the desired position.
 6. Apparatuscomprising: a steerable catheter, comprising a thumb control, which isadapted to control a deflection of a distal tip of the catheter; and arobot, comprising: an end-effector, adapted to be coupled to the thumbcontrol; and a controller, adapted to drive the end-effector to deflectthe distal tip by manipulating the thumb control.
 7. Apparatus for usewith a steerable catheter that includes controls adapted to control adeflection of a distal tip of the catheter, which controls are generallyoptimized for manipulation by a human hand, the apparatus comprising arobot, comprising: at least one end-effector, adapted to be coupled toat least a portion of the controls; and a controller, adapted to drivethe at least one end-effector to deflect the distal tip by inducingmotion of the portion of the controls that generally mimics motion ofthe portion of the controls induced when a human hand manipulates thecontrols.
 8. The apparatus according to claim 7, wherein the controlleris adapted to drive the end-effector to deflect the distal tip by movingthe portion of the controls longitudinally with respect to alongitudinal axis of the catheter.
 9. The apparatus according to claim7, wherein the controls are adapted to control a roll of the distal tip,wherein the robot comprises a roll end-effector, adapted to be coupledto the controls, and wherein the controller is adapted to drive the rollend-effector to roll the distal tip by inducing motion of the controlsthat generally mimics motion of the controls induced when a human handmanipulates the controls.
 10. The apparatus according to claim 7,wherein the controls are adapted to advance and withdraw the catheter,wherein the robot comprises a longitudinal motion end-effector, adaptedto be coupled to the controls, and wherein the controller is adapted todrive the longitudinal motion end-effector to perform, by inducingmotion of the controls that generally mimics motion of the controlsinduced when a human hand manipulates the controls, at least one actionselected from the list consisting of: advancing the catheter andwithdrawing the catheter.
 11. The apparatus according to claim 7,comprising a computer pointing device, adapted to receive an indicationof a desired position of the distal tip, wherein the catheter includes aposition sensor, fixed in a vicinity of the distal tip, and adapted togenerate a position signal, and wherein the controller is adapted toreceive the position signal, and, responsive thereto, to drive theend-effector to position the distal tip at the desired position. 12.Apparatus comprising: a steerable catheter, comprising controls adaptedto control a deflection of a distal tip of the catheter, which controlsare generally optimized for manipulation by a human hand; and a robot,comprising: at least one end-effector, adapted to be coupled to at leasta portion of the controls; and a controller, adapted to drive the atleast one end-effector to deflect the distal tip by inducing motion ofthe portion of the controls that generally mimics motion of the portionof the controls induced when a human hand manipulates the controls. 13.Apparatus comprising: a steerable catheter, comprising: a distal tipadapted to be controllably deflectable in no more than two directionsfor any given rotation of the distal tip, such that a set of all pointsto which the tip can be deflected at the given rotation forms adeflection curve for the given rotation; and a position sensor, fixed ina vicinity of the distal tip, and adapted to generate a position signal;a robot, adapted to manipulate a proximal end of the catheter; and acontrol unit, adapted to: receive the position signal, and position thedistal tip at a target by driving the robot to: position the distal tipin a vicinity of the target, responsive to the position signal, rotatethe proximal end in order to cause the distal tip to roll to a rotationthe deflection curve of which includes the target, the rotationdetermined responsive to the position signal, and deflect the distal tipalong the deflection curve to the target.
 14. The apparatus according toclaim 13, wherein the distal tip is adapted to be controllably deflectedin no more than one direction for the given rotation of the distal tip.15. The apparatus according to claim 13, wherein the control unit isadapted to position the distal tip in the vicinity of the target bypositioning the distal tip so that the deflection curve of at least onerotation of the distal tip includes the target.
 16. The apparatusaccording to claim 13, comprising a computer pointing device, adapted toreceive an indication of a position of the target, wherein the controlunit is adapted to drive the robot to position the distal tip at theposition of the target, responsive to the position signal.
 17. Theapparatus according to claim 13, wherein the position sensor is adaptedto generate the position signal having six dimensions of position andorientation information.
 18. Apparatus comprising: a steerable catheterhaving a distal tip, the catheter comprising a position sensor, fixed ina vicinity of the distal tip, and adapted to generate a position signal;a robot, adapted to be coupled to a proximal end of the catheter; and acontrol unit, adapted to: drive the robot to apply rotation to theproximal end of the catheter, receive the position signal, responsive tothe position signal, determine a roll of the distal tip, and responsiveto a determination that the roll lags the rotation, drive the robot tomove a portion of the proximal end of the catheter.
 19. The apparatusaccording to claim 18, wherein the control unit is adapted to drive therobot to move the portion of the proximal end of the catheter to performat least one action selected from the list consisting of: straighteningthe distal tip and deflecting the distal tip.
 20. The apparatusaccording to claim 18, wherein the control unit is adapted to drive therobot to move the portion of the proximal end of the catheter to effecttranslational back and forth motion of the distal tip.
 21. The apparatusaccording to claim 18, wherein the control unit is adapted to drive therobot to move the portion of the proximal end of the catheter to performat least one action selected from the list consisting of: advancing thedistal tip and withdrawing the distal tip.
 22. The apparatus accordingto claim 18, wherein the position sensor is adapted to generate theposition signal having six dimensions of position and orientationinformation.
 23. The apparatus according to claim 18, wherein thecontrol unit is adapted to move the portion of the proximal end of thecatheter to jiggle the distal tip.
 24. The apparatus according to claim23, wherein the control unit is adapted to jiggle the distal tip byrotating the proximal end of the catheter.
 25. A method for use with asteerable catheter that includes a thumb control adapted to control adeflection of a distal tip of the catheter, the method comprising:coupling a robotic end-effector to the thumb control; and driving theend-effector to deflect the distal tip by manipulating the thumbcontrol.
 26. The method according to claim 25, wherein manipulating thethumb control comprises moving the thumb control longitudinally withrespect to a longitudinal axis of the catheter.
 27. The method accordingto claim 25, wherein the catheter includes a handle, adapted to controla roll of the distal tip, and comprising: coupling a handle end-effectorto the handle; and driving the handle end-effector to roll the distaltip by manipulating the handle.
 28. The method according to claim 25,wherein the catheter includes a handle, adapted to advance and withdrawthe catheter, and comprising: coupling a handle end-effector to thehandle; and driving the handle end-effector to perform, by manipulatingthe handle, at least one action selected from the list consisting of:advancing the catheter and withdrawing the catheter.
 29. The methodaccording to claim 25, comprising: receiving an indication of a desiredposition of the distal tip; receiving a position signal generated from avicinity of the distal tip; and driving the end-effector to position thedistal tip at the desired position, responsive to the position signal.30. A method for use with a steerable catheter that includes controlsadapted to control a deflection of a distal tip of the catheter, whichcontrols are generally optimized for manipulation by a human hand, themethod comprising: coupling at least one robotic end-effector to atleast a portion of the controls; and driving the at least oneend-effector to deflect the distal tip by inducing motion of the portionof the controls that generally mimics motion of the portion of thecontrols induced when a human hand manipulates the controls.
 31. Themethod according to claim 30, wherein inducing the motion of the portionof the controls comprises moving the portion of the controlslongitudinally with respect to a longitudinal axis of the catheter. 32.The method according to claim 30, wherein the controls are adapted tocontrol a roll of the distal tip, and comprising: coupling a rollend-effector to the controls; and driving the roll end-effector to rollthe distal tip by inducing motion of the controls that generally mimicsmotion of the controls induced when a human hand manipulates thecontrols.
 33. The method according to claim 30, wherein the controls areadapted to advance and withdraw the catheter, and comprising: coupling alongitudinal motion end-effector to the controls; and driving thelongitudinal motion end-effector to perform, by inducing motion of thecontrols that generally mimics motion of the controls induced when ahuman hand manipulates the controls, at least one action selected fromthe list consisting of: advancing the catheter and withdrawing thecatheter.
 34. The method according to claim 30, comprising: receiving anindication of a desired position of the distal tip; receiving a positionsignal generated from a vicinity of the distal tip; and driving theend-effector to position the distal tip at the desired position,responsive to the position signal.
 35. A method for use with a steerablecatheter having a distal tip adapted to be controllably deflectable inno more than two directions for any given rotation of the distal tip,such that a set of all points to which the tip can be deflected at thegiven rotation forms a deflection curve for the given rotation, themethod comprising: receiving a position signal from a vicinity of thedistal tip; and robotically positioning the distal tip at a target by:robotically positioning the distal tip in a vicinity of the target,responsive to the position signal, robotically rotating the proximal endin order to cause the distal tip to roll to a rotation the deflectioncurve of which includes the target, the rotation determined responsiveto the position signal, and robotically deflecting the distal tip alongthe deflection curve to the target.
 36. The method according to claim35, wherein robotically positioning the distal tip in the vicinity ofthe target comprises robotically positioning the distal tip so that thedeflection curve of at least one rotation of the distal tip includes thetarget.
 37. The method according to claim 35, comprising receiving anindication of a position of the target, wherein robotically deflectingthe distal tip comprises robotically deflecting the distal tip to theposition of the target, responsive to the position signal.
 38. Themethod according to claim 35, wherein receiving the position signalcomprises receiving the position signal, the position signal having sixdimensions of position and orientation information.
 39. A method for usewith a steerable catheter having a distal tip and a proximal end, themethod comprising: robotically rotating the proximal end of thecatheter; receiving a position signal from a vicinity of the distal tipof the catheter; responsive to the position signal, determining a rollof the distal tip; and responsive to a determination that the roll lagsthe rotation, robotically moving a portion of the proximal end of thecatheter.
 40. The method according to claim 39, wherein roboticallymoving the portion of the proximal end of the catheter comprisesrobotically performing at least one action selected from the listconsisting of: straightening the distal tip and deflecting the distaltip.
 41. The method according to claim 39, wherein robotically movingthe portion of the proximal end of the catheter comprises roboticallytranslating the distal tip back and forth.
 42. The method according toclaim 39, wherein robotically moving the portion of the proximal end ofthe catheter comprises robotically performing at least one actionselected from the list consisting of: advancing the distal tip andwithdrawing the distal tip.
 43. The method according to claim 39,wherein receiving the position signal comprises receiving the positionsignal, the position signal having six dimensions of position andorientation information.
 44. The method according to claim 39, whereinrobotically moving the portion of the proximal end of the cathetercomprises robotically jiggling the distal tip.
 45. The method accordingto claim 44, wherein robotically jiggling the distal tip comprisesrobotically rotating the proximal end of the catheter.